Landfills
Location Restrictions
EPA regulations establish special siting restrictions and performance standards for six types of MSWLF site locations: airports, 100-year floodplains, wetlands, fault areas, seismic impact zones, and unstable areas. These six types of locations are sensitive areas that warrant additional regulatory controls. While all six location restrictions apply to new and laterally expanding MSWLF units, existing units are subject only to airport safety, floodplain and unstable area controls. Because these landfill siting regulations involve substantial geological investigation, certain terms used in the regulations are unusually technical.
Airport Safety Controls
Landfills can attract birds seeking food or nesting sites; therefore, landfills that are located near an airport may pose a risk of collisions between birds and aircraft. The airport safety restrictions define a danger zone in which special care must be taken to ensure that the likelihood of collisions between birds and aircraft is reduced. These provisions apply to new MSWLFs, existing MSWLFs and lateral expansions located within 10,000 feet of any airport runway used by turbojet aircraft, or within 5,000 feet of any runway end used by piston-type aircraft only. The owner and operator of any unit located within these areas must demonstrate that the management practices of the landfill will minimize the incidents of bird hazards for aircraft.
Provided the owner and operator can make this demonstration, the airport safety criteria do not prohibit the disposal of solid waste within the specified distances. Likewise, the airport safety restrictions do not impact the location of airports or airport runways. In accordance with Federal Aviation Administration (FAA), however, municipal landfills and lateral expansions proposed within a five-mile radius of any airport runway end used by turbojet or piston-type aircraft must notify the affected airport and the FAA in writing of such a proposal.
The Aviation Investment and Reform Act for the 21st Century, which includes provisions that amend the MSWLF location criteria, was signed into law on April 5, 2000. The amendments come after Congress found that collisions between aircraft and birds have resulted in fatal accidents and pose special dangers to smaller aircraft. Since landfills have an inherent nature to attract birds, the law prohibits the location of new MSWLFs within six miles of airports served by general aviation aircraft and regularly scheduled flights of aircraft designed for 60 passengers or less. This restriction does not apply to existing landfills or expansions of existing landfills.
Floodplain Controls
Floodplain regulations establish guidelines that must be followed when a new or existing MSWLF or a lateral expansion is located in a 100-year floodplain. A unit subject to these provisions must be designed and operated to minimize its effect on both the 100-year flood flow and the temporary water storage capacity of the floodplain. The unit’s owner and operator must provide evidence that the landfill will not restrict the flow of the 100-year flood, reduce the temporary water storage capacity of the floodplain, or result in washout of solid waste.
Wetlands Controls
Swamps, bogs, marshes, and other wetlands are unique, critical ecosystems that serve an important role in flood control, help filter wastes from water, provide an important breeding ground for fish and wildlife, and constitute an important recreational resource. EPA has placed a high priority on wetlands protection, but believes an outright ban of new MSWLFs or lateral expansions in wetlands could severely restrict the sites available for new or expanding landfills. Thus, the Agency developed guidelines for the limited siting of MSWLFs in wetlands. New units or lateral expansions are banned from wetlands unless the owner and operator make the following demonstrations to the Director of an approved state:
rebut the presumption that a practicable alternative site is available
show that landfill construction and operation will not violate certain state and federal standards designed to protect water quality and wildlife
demonstrate that the MSWLF unit will not cause or contribute to significant degradation of wetlands
demonstrate that steps were taken to achieve no net loss of wetlands.
Because these demonstrations must satisfy the Director of an approved state, §258.12(a) effectively bans the siting of new MSWLF units and lateral expansions in wetlands in unapproved states. The Agency intends to keep these wetlands location restrictions consistent with all CWA regulatory modifications. As §404 of the CWA evolves in accordance with the wetlands protection program, EPA will modify relevant portions of §258.12 accordingly.
Fault Area Controls
Fault area restrictions ban the siting of new MSWLFs and lateral expansions within 200 feet of a fault that has experienced displacement in Holocene time (i.e., the past 11,000 years). This restriction reflects the Agency’s belief that, in general, a 200-foot buffer zone is adequate to protect engineered structures, such as a new MSWLF, from seismic damage. In a state with an approved permitting program, however, the owner and operator may demonstrate that a setback distance less than 200 feet will prevent damage to the structural integrity of the unit and will be protective of human health and the environment.
Seismic Impact Zones
In unapproved states, new MSWLFs and lateral expansions cannot be sited in a seismic impact zone. In a state with an approved permitting program, however, a MSWLF may be located in a seismic impact zone if the owner and operator can prove that all containment structures, liners, leachate collection systems, and surface water control systems are designed to resist the anticipated movement in geologic features at the site.
Unstable Area Controls
Any location susceptible to events or forces capable of impairing a landfill’s structural integrity is classified as an unstable area. Owners and operators must assess onsite and local factors, including soil conditions and geologic features, to determine whether an area is unstable. Unstable areas can include poor foundation conditions, areas susceptible to mass movement, and karst topography. New and existing MSWLFs and lateral expansions must not be located in an unstable area unless the owner and operator can demonstrate that engineering measures in the unit’s design are sufficient to ensure that the integrity of structural components (e.g., composite liner and final cover) will not be disrupted.
—From www.epa.gov/osw/inforesources/pubs/training/mswlf05.pdf